Detectable warning plate

ABSTRACT

A detectable warning plate having integrally cast lugs. The lugs may extend from the undersurface of the plate so that they can be entrapped within concrete during installation. The plate may define a vent hole through the plate above each lug to permit air to escape from beneath the dome plate during installation. The plate may include one or more integral support ribs that extend downwardly from the plate. The support ribs may extend around the plate near the periphery. The lugs may be extensions of the support ribs.

BACKGROUND OF THE INVENTION

The present invention relates to municipal/construction castings and more particularly to detectable warning plates.

Detectable warning plates are widely used as a tactile warning for the blind in sidewalks, walkways and other similar structures. Typically, detectable warning plates are embedded in the sidewalk and have an upper surface with an arrangement of regularly-spaced protrusions in the shape of truncated domes. The size, shape and arrangements of protrusions are specified in the ADA Accessibility Guidelines for Detectable Warnings. These specifications are intended to provide uniform warnings that can be readily detected by the blind. In some applications, the prescribed pattern of protrusions is formed directly in the concrete. Unfortunately, it can be difficult to manufacture protrusions in concrete that are uniform and of consistently high quality. Further concrete protrusions are highly susceptible to wear and other damage.

Accordingly, a variety of detectable warning products have been developed to be embedded in concrete and provide the prescribed pattern of protrusions. Detectable warning plates are manufactured from materials ranging from plastic to iron. Experience has revealed that detectable warning products manufactured from plastics, composites and other relatively light materials are more susceptible to wear and more prone to damage from snow plows and other maintenance equipment. Further, conventional detectable warning products of essentially all types can be susceptible to separation from the concrete in which they are embedded. For example, external forces, such as a snow plow, may break the detectable warning plate away from the concrete. Further, the expansion and contraction associated with temperature changes can also cause a detectable warning plate to separate from the concrete. Conventional detectable warning plates have been provided with interlocking structures on their undersurface. It can, however, be difficult to get the concrete to adequately flow around the interlocking structure and these conventional efforts have met with only limited success.

Accordingly, there remains a long felt and unmet need for a detectable warning product that is durable, easily installed, remains embedded and does not warp during installation or use.

SUMMARY OF THE INVENTION

The aforementioned problems are overcome by the present invention wherein a detectable warning plate is provided with integral locking lugs. In one embodiment, the plate includes two lugs arranged in a regular pattern on the bottom of the plate. In this embodiment, each lug may extend downwardly from the undersurface of the plate and may be somewhat C-shaped. The lugs are spaced a sufficient distance from the undersurface of the plate to readily permit the flow of concrete around the lug. The plate may be cast from iron and may include lugs that are formed integral with the plate during casting.

In one embodiment, the plate may define a vent hole extending vertically through the plate above each lug. The vent holes permit air to escape from beneath the plate during installation as concrete flows in around the lugs.

In another embodiment, the plate includes support ribs to strengthen the plate and, among other things, reduce the possibility of warping or other deformation during manufacture. In one embodiment, the support ribs extend from the undersurface of the plate and extend around the plate near its periphery. In another embodiment, the support ribs are arranged in an X-shaped configuration with its intersection located at the approximate center of the plate. In these embodiments, the lugs may be extensions of the support rib.

If desired, the upper surface of the detectable warning plate may be textured to improve traction. The design and configuration of the texture may vary from application to application. For example, this texture may extend over all or a portion of each truncated dome-like protrusion, and/or over the surfaces between the protrusions.

The present invention provides a detectable warning plate that is durable and easy to install. The lugs provide an integral structure that can be embedded within concrete to provide a durable and lasting attachment. The broad spacing of the lugs permits wet concrete to easily flow around the lugs to interlock the plate and the concrete. The vent holes facilitate installation by permitting air trapped within the lugs to escape as the wet concrete flows around the lugs. Otherwise, air pockets trapped under the plate might have a significant adverse impact on the interlock between the plate and the concrete. The integral support ribs dramatically reduce the risk of warping during manufacture and may provide additional structure for the lugs.

These and other objects, advantages, and features of the invention will be readily understood and appreciated by reference to the detailed description of the current embodiment and the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top perspective view of a detectable warning plate according to an embodiment of the invention.

FIG. 2 is a bottom perspective view of the detectable warning plate.

FIG. 3 is a perspective view showing the detectable warning plate embedded in a sidewalk.

FIG. 4 is a right side elevational view of the detectable warning plate.

FIG. 5 is an enlarged perspective view of a portion of the detectable warning plate showing a single protrusion.

FIG. 6 is a bottom plan view of the detectable warning plate.

FIG. 7 is a sectional view showing the detectable warning plate shortly after being embedded in wet concrete.

FIG. 8 is a sectional view similar to FIG. 7 showing the detectable warning plate after the wet concrete has filled in around the lugs.

FIG. 9 is a perspective view of a first alternative detectable warning plate.

FIG. 10 is a top plan view of the first alternative detectable warning plate.

FIG. 11 is a bottom plan view of the first alternative detectable warning plate.

FIG. 12 is a sectional view of the first alternative detectable warning plate taken along line 12-12 of FIG. 10.

FIG. 13 is a top view showing a plurality of the first alternative detectable warning plates installed at a curb.

FIG. 14 is a bottom perspective view of a second alternative detectable warning plate.

FIG. 15 is a bottom perspective view of a third alternative detectable warning plate.

DESCRIPTION OF THE CURRENT EMBODIMENT

A detectable warning plate in accordance with an embodiment of the present invention is shown in FIGS. 1 and 2, and is generally designated 10. The detectable warning plate 10 generally includes a main body 12 and a plurality of lugs 14 a-d that extend from the undersurface of the plate 10. As perhaps best shown in FIG. 3, the detectable warning plate 10 may be installed in sidewalks S, walkways and other similar structures to signal the end of the sidewalk to the blind. During installation, the lugs 14 a-d are embedded in wet concrete to lock the plate 10 in place within the concrete. If desired, a plurality of detectable warning plates 10 may be installed adjacent to each other to provide a warning area of the desired size.

Referring now to FIGS. 1, 2 and 4, the detectable warning plate 10 generally includes a main body 12 and a plurality of lugs 14 a-d. In the illustrated embodiment, the main body 12 is a generally rectangular plate. However, its shape may vary from application to application as desired. For example, the main body 12 may be round, oval, square or irregular in shape. The dimensions of the plate 10 may also vary from application to application depending largely on the structural requirements and the environment in which the plate 10 is to be installed. The main body 12 generally includes an upper surface 16 and a lower surface 18. In the illustrated embodiment, an arrangement of protrusions 30 extend upwardly from the upper surface 16 of the main body 12 in compliance with applicable ADA Accessibility Guidelines for Detectable Warnings. FIG. 5 is an enlarged view of a portion of the plate 10 showing a single protrusion 30. As shown, each protrusion 30 is shaped as a truncated spherical dome having a planar top surface 32. The upper surface 16 of the plate 10 may alternatively include protrusions of other sizes, shapes and arrangements. The upper surface 16 may optionally be textured to provide improved traction. Given the practical difficulties of showing the texture in all Figs., the texture is shown only in FIG. 5. In the illustrated embodiment, the planar portions of the upper surface 16 of the plate 10 and the planar top surface 32 of each protrusion 30 may be textured (See FIG. 5). As shown in FIG. 5, the curved surfaces of protrusions 30 in the illustrated embodiment are not textured. The plate 10 may include essentially any pattern of texturing, but in the illustrated embodiment, the texturing includes a plurality of regularly spaced diamond-shaped elements 31.

The plate 10 may optionally include support ribs. In the illustrated embodiment, support ribs 20 a-b extend from the lower surface 18 of the main body 12 (See FIGS. 2 and 6). The support ribs 20 a-b of this embodiment are arranged in a generally X-shaped configuration. As shown, the support ribs 20 a-b may extend along imaginary lines interconnecting opposite comers of the rectangular shaped main body 12. In this embodiment, the two support ribs 20 a-b intersect at the approximate center of the main body 12. The precise size of the support ribs 20 a-b may vary from application to application depending in large part on the specific characteristics of the main body 12. For example, the depth and width of the support ribs 20 a-b will typically be selected to provide sufficient strength to prevent warping of the plate 10 during manufacture. The number, size, shape and configuration of the support ribs may vary from application to application, as desired.

As noted above, the plate 10 includes lugs 14 a-d that extend from the undersurface of the main body 12. The lugs 14 a-d may be integrally formed with the plate 10 or may be separately manufactured and attached to the plate 10. In the illustrated embodiment, the plate 10 includes four lugs 14 a-d extending from and in alignment with the support ribs 20 a-b. The lugs 14 a-d may alternatively be separate from the support ribs 20 a-b. As shown, the lugs 14 a-d of this embodiment are generally C-shaped, each having an interlock section 34 and opposite end sections 36 and 38. The end sections 36 and 38 are joined to the lower surface 18 of the main body 12. The interlock section 34 of each lug 14 a-d is spaced a sufficient distance away from the main body 12 to allow the free flow of concrete around the lugs 14 a-d during installation in wet concrete. In the illustrated embodiment, each lug is spaced approximately 33 mm from the lower surface 18. The number, size, shape, arrangement and configuration of the lugs may vary from application to application depending in large part on the characteristics of the main body 12, the characteristics of the concrete (or other foundation in which the plate 10 is to be embedded) and the desired strength of the bond between the plate 10 and the foundation.

The main body 12 may define a plurality of vent holes 40 a-d that permit air to vent from beneath the plate 10 during installation as concrete flows around the lugs 14 a-d. In the illustrated embodiment, a single vent hole 40 a-d is defined vertically through the main body 12 in alignment with the approximate center of each lug 14 a-d. As a result, the illustrated embodiment includes four vent holes 40 a-d. The number, size, shape and location of the vent holes 40 a-d may vary from application to application as desired. For example, two or more vent holes may be defined at each lug. By increasing the number of vent holes, the size of each vent hole may be decreased.

The detectable warning plate 10 may be installed in wet concrete using conventional techniques and apparatus. For example, the plate 10 may be placed in wet concrete as the sidewalk or other infrastructure is being formed. The plate 10 is placed in the concrete after the concrete has been poured and before the concrete has cured to the point where it has lost the ability to flow. The plate 10 will typically be installed so that the planar upper surface 16 of the plate 10 is aligned with the top surface of the surrounding concrete. The plate 10 is positioned with the lugs 14 a-d pushed down into the wet concrete. When placed in wet concrete, the inherent flowing nature of the wet concrete will cause the concrete to flow around the lugs 14 a-d (See FIG. 7). As the concrete flows around the lugs, air trapped under the plate 10 is free to vent from beneath the plate 10 through the vent holes 40 a-d. In this way, the vent holes 40 a-d prevent air from being trapped beneath the plate 10, thereby permitting the concrete to completely entrapment of the lugs within the concrete (See FIG. 8).

The present invention may be manufactured using any of a variety of conventional manufacturing techniques. For example, the detectable warning plate 10 may be manufactured using conventional cast iron manufacturing techniques and apparatus. In the illustrated embodiment, the plate 10 is cast as a one-piece component having integral support ribs 20 and integral lugs 12 a-d. Although plate 10 is manufactured from iron, it may alternatively be manufactured from other materials as appropriate for the specific application.

A detectable warning plate 110 in accordance with another embodiment of the present invention is shown in FIGS. 9-13. In this embodiment, the plate 110 includes a slight taper and a slight curve so that a plurality of plates may be positioned adjacent to one another to form a curved warning zone. For example, FIG. 13 shows four detectable warning plates 110 mounted adjacent to one another in an exemplary sidewalk application. The amount of taper or curve in each plate may vary from application to application as desired. However, in the illustrated embodiment, the wider curved edge 111 of the plate follows an 18⅞ inch radius of curvature and it takes 20 plates to complete a full 90 degree turn. As shown in FIGS. 9 and 11, the plate 110 includes a main body 112 having an upper surface 116 and a lower surface 18. A plurality of protrusions 130 extend from the upper surface 116 in a regular pattern. In this case, the protrusions 130 are truncated spherical domes as described above in connection with plate 10. A plurality of lugs 114 a-b extend from the undersurface of the plate 110. In the embodiment of FIGS. 9-13, the plate 11—includes two lugs 114 a and 114 b located adjacent opposite longitudinal edges of the plate 110. The number, size, location and configuration of the lugs 1 14 a-b may vary from application to application as desired. The plate 110 also includes a support rib with segments 120 a-d that extend from the lower surface 18 of the plate 110 (See FIG. 12). In this embodiment, the support rib segments 120 a-d extend around the plate 110 adjacent to the periphery of the plate 110. As perhaps best shown in FIG. 12, the lugs 114 a-b are integral with the support rib segments 120 a-d. The number, size, shape and configuration of the support rib and support rib segments 120 a-d may vary from application to application. The plate 110 defines a plurality of vent holes 140 a-b—one vent hole 140 a or 140 b in alignment with each lug 114 a-b. The vent holes 140 a-b are of sufficient size to permit air to escape from beneath the plate 110 as concrete flows into the space between the lower surface 118 and the lugs 114 a-b. The plate 110 may also include one or more additional vent holes that permit air to vent from beneath the plate 110 during installation. For example, plate 110 includes a vent hole 141 that facilitates venting of air from within the boundary of the support rib segments 120 a-d.

Detectable warning plates 210, 310 and 410 in accordance with three additional alternative embodiments of the present invention are shown in FIGS. 14, 15 and 16, respectively. These three alternative embodiments illustrated different plate shapes and lug configurations. FIG. 14 illustrates a generally square plate 210 having a peripheral support rib with segments 220 a-d and two lugs 214 a-b. The lugs 214 a-b are integral with the support ribs segments 220 a-d. The plate 210 defines a first pair of vent holes 240 a-b in alignment with the lugs 214 a-b and a second pair of vent holes 241 a-b disposed inside the boundary of the support rib segments 220 a-d. Although not shown, the upper surface of the plate 210 may include a plurality of protrusions, such as the truncated spherical domes described above. FIG. 15 illustrates a rectangular plate 310 having a peripheral support ribs with segments 320 a-d and two lugs 314 a-b. The lugs 314 a-b are integral with the support rib segments 320 a-d, and are disposed toward opposite ends of the plate 310. The plate 310 defines a first pair of vent holes 340 a-b in alignment with the lugs 314 a-b and a second pair of vent holes 341 a-b disposed inside the boundary of the support rib segments 320 a-d. Although not shown, the upper surface of the plate 310 may include a plurality of protrusions, such as the truncated spherical domes described above. Finally, FIG. 16 illustrates a rectangular plate 410 that is quite similar to plate 310. Plate 410 includes a peripheral support rib with segments 420 a-d and two lugs 414 a-b. The lugs 414 a-b are integral with the support rib segments 420 a-d, and are disposed toward opposite ends of the plate 410. The plate 410 defines a first pair of vent holes 440 a-b in alignment with the lugs 414 a-b and a second pair of vent holes 441 a-b disposed inside the boundary of the support rib segments 420 a-d. Although not shown, the upper surface of the plate 410 may include a plurality of protrusions, such as the truncated spherical domes described above. The embodiments of FIGS. 14-16 are illustrated to provide examples of alternative embodiments of the present invention, and not to provide limitations on the scope of the invention. Each of these embodiments may include any of the variations described above in connection with plate 10 and plate 110.

The above description is that of the current embodiment of the invention. Various alterations and changes can be made without departing from the spirit and broader aspects of the invention as defined in the appended claims, which are to be interpreted in accordance with the principles of patent law including the doctrine of equivalents. Any reference to claim elements in the singular, for example, using the articles “a,” “an,” “the” or “said,” is not to be construed as limiting the element to the singular. 

1. A warning plate to be embedded in concrete comprising: a main body having a top surface and a bottom surface, said main body including a plurality of protrusions extending upwardly from said top surface; a plurality of lugs extending downwardly from said bottom surface, each of said lugs defining a through-hole of sufficient size to permit free flow of concrete through said through-hole of each of said lugs; and wherein said main body defines at least one vent hole extending through said main body from said top surface to said bottom surface adjacent to each lug, whereby air is free to vent from beneath said plate during installation of said plate in concrete.
 2. The plate of claim 1 wherein said plurality of lugs includes at least two lugs.
 3. The plate of claim 2 further including a support rib extending downwardly from said bottom surface.
 4. The plate of claim 2 further including a support rib extending downwardly from said bottom surface, said support rib extending near a periphery of the plate.
 5. The plate of claim 4 wherein at least one of said lugs extends downwardly from said support ribs.
 6. The plate of claim 1 wherein each of said vent holes is in substantial vertical alignment with a corresponding one of said through-holes.
 7. The plate of claim 1 wherein said protrusions are of uniform shape and are regularly spaced over said top surface of said main body; and wherein each of said protrusions includes a planar top surface, said planar top surface of each of said protrusions being textured.
 8. A detectable warning plate comprising: a main cast body having a top surface and a bottom surface, said main cast body including a plurality of protrusions extending upwardly from said top surface; at least one lug integrally cast with said main cast body extending downwardly from said bottom surface, said lug having an interlock segment spaced from said bottom surface a sufficient distance to permit free flow of concrete between said interlock segment and said bottom surface; and at least one support rib integrally cast with said main cast body extending across a portion of said main cast body, said support rib extending downwardly from said bottom surface.
 9. The plate of claim 8 wherein said support rib extends substantially around the plate near a peripheral edge of the plate.
 10. The plate of claim 9 wherein said lug extends from said support rib, whereby said lug is supported at least in part by said support rib.
 11. The plate of claim 10 wherein said main cast body defines at least one vent hole extending through said main cast body from said top surface to said bottom surface adjacent in substantial vertical alignment with said lug, whereby air is free to escape from beneath said plate during installation of said plate in concrete.
 12. The plate of claim 11 further defined as including at least two lugs extending downwardly from said bottom surface, each of said lugs extending from said support rib.
 13. The plate of claim 12 wherein said lugs are disposed on opposite sides of the plate.
 14. The plate of claim 13 wherein each of said lugs is generally C-shaped having a pair of opposed ends extending from opposite ends of said interlock segment and being joined to said main cast body, whereby each of said lugs defines a central through-hole through which wet concrete may flow.
 15. A cast detectable warning plate to be embedded in concrete comprising: a main body having a top surface and a bottom surface, said main body including a plurality of protrusions extending upwardly from said top surface, said protrusion being regularly space and of uniform size and shape, said main body including a support rib extending downwardly from said bottom surface, said support rib being integrally formed with said main body; a plurality of lugs extending downwardly from said bottom surface, said lugs being integrally formed with said main body, each of said lugs defining a through-hole of sufficient size to permit free flow of wet concrete through said through-hole; wherein said main body defines at least one vent hole extending through said main body from said top surface to said bottom surface adjacent to each through-hole, whereby air is free to escape from beneath said plate during installation of said plate in concrete.
 16. The plate of claim 15 wherein said support rib extends along at least a portion of a periphery of said main body.
 17. The plate of claim 16 wherein each of said lugs extends from said support rib.
 18. The plate of claim 16 wherein each of said lugs is generally C-shaped having an interlock section and a pair of ends extending from opposite ends of said interlock section, said opposite ends being integrally joined with said main body.
 19. The plate of claim 18 wherein each of said protrusions includes a top planar surface.
 20. The plate of claim 19 wherein each of said top planar surfaces is textured to provide improved traction. 